Abstract:
Hexavalent chromium [Cr(VI)] contamination in water sources presents significant
environmental and health hazards, adversely affecting aquatic ecosystems, soil integrity, and
the food chain. Human exposure to Cr(VI) can lead to severe health complications, including
fatal outcomes. Consequently, developing efficient water treatment methods is crucial to
ensuring safe and equitable access to clean drinking water. Among various remediation
strategies, adsorption using biochar has gained prominence as a cost-effective, simple, High
removal efficiency, and minimal risk of secondary pollution. In this study, sugarcane bagasse
(SB) biochar from sugarcane bagasse, an abundant and renewable biomass resource, was
synthesized via an economical process involving NaOH and H₃PO₄ treatment, followed by
carbonization, and its adsorptive removal of Cr(VI) from aqueous solution was examined.
Proximate analyses were conducted on raw and acid-heat-treated SB biochar. Pretrial
screening identified H₃PO₄-treated SB biochar as the most effective adsorbent, warranting
further characterization through XRD, FTIR, and SEM. Batch adsorption experiments were
performed to assess the impact of key operational parameters, including temperature, contact
time, pH, initial Cr(VI) concentration, and adsorbent dosage. The optimal conditions for
Cr(VI) removal were a contact time 7 h, pH 3.0, initial Cr(VI) concentration of 50 mg/L,
adsorbent dosage of 2 g/L, and a carbonization temperature of 400°C. Equilibrium adsorption
data aligned well with the Freundlich isotherm model (R² = 0.999), and the maximum Cr(VI)
adsorption capacity of SB biochar was found to be 54.745 mg/g. The adsorption kinetics
followed the pseudo-second-order (PSO) model (R² = 0.998), suggesting a chemisorption
dominated process. The potential for adsorbent recyclability highlights the feasibility of SB
derived biochar for sustainable Cr(VI) remediation in wastewater treatment. Therefore, this
study underscores the environmental and economic benefits of repurposing industrial waste
into high-performance adsorbent materials.
